Sustainable Transportation Design In the United States: Background, Current Initiatives and Optimization

Abstract

Decades of increased highway maintenance and construction, the constant use of finite resources, the severity of highway accidents, increased congestion, harmful emissions, and other negative environmental impacts have created an unsustainable highway system in the United States. While the modern environmental movement began in the 1960’s, American’s have only recently realized that something must be done regarding the environmental impacts due to the development of transportation systems. To date, there isn’t a single most commonly used definition of sustainable transportation, however; sustainable transportation can be linked to sustainable development which is most commonly defined as, “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. Thus far, much of the focus on sustainable transportation has been on green-house gases (GHG’s) and other harmful emissions of the automobiles which use U.S. highways. While this is indeed a significant factor negatively affecting the environment, economy and social well-being of American’s, it is not the only issue with transportation systems in the United States. Since the development of the modern federal highway system began in the 1950’s, highway design, construction, operations and maintenance efforts have enjoyed nearly infinite use of America’s valuable resources. Unfortunately the use of these valuable resources is now outpacing the rate at which they can be renewed, which could soon result in the elimination or unavailability of certain resources if the development of America’s roadways doesn’t change. In response to this new dilemma, several initiatives have recently been introduced across America to address the unsustainable nature of transportation projects. Some of these include sustainable rating systems similar to the LEED (Leadership in Energy and Environmental Design) rating system for buildings developed by the United States Green Building Council (USGBC). Most of these systems are in the infant stages of development and implementation and the actual environmental benefits that result from using these systems is yet to be seen. There are several pros and cons for sustainable transportation rating systems. The pros are the environmental and sustainable benefits that result in using a system directed toward sustainability. The cons are a little more complex. They include the unknowns like the time, cost and effort for certification, the integrity of the system, and the question of whom, in the end, is responsible for certification. Even so, with the success of the LEED rating system, it would be surprising if these systems were unsuccessful. However, just because these systems are expected to succeed, does not infer that other avenues toward sustainable transportation should not be explored. Sustainable transportation optimization is a new concept presented in this paper which combines rating systems with linear programming models by using cost and public input as well as site specific environmental concerns as part of the decision-making process for inclusion of sustainable measures in a given project. Like sustainable transportation rating systems, further research is needed to determine if it is worth the extra effort that may be required for implementing a sustainable transportation optimization system.